Mine detection device



Jufiy 1, 1946- M. H. LbUGI-LNAN E MINE DETECTION DEVICE 1 Filed June 18,1943 2 Shets-Sheet 1 t 2/ 113F320 2a 11 f 23 ATTOHVE'Y.

July 16, 194-.

M. H. LOUGHNANE MINE DETECTION DEVICE Filed June 18, 1943 2 She ecs-Sheet 2 ISTRIEUTIJR M A A I'EIEI Patented July 16, 1946 Michael HenryLoughnane, Little Falls, N. J.

Application June 18, 1943, Serial No. 491,338

4 Claims.

This invention relates to improvements in mine detection devices andspecifically it relates to a system employing a plurality of propelledand controlled torpedo-like detection vessels operated in front of theship to be protected and an electrical detection circuit comprised inthe control cables of said detection vessels whereby approaching minesare automatically indicated on the ship to be protected.

The protection of ships against mines is a problem which is of greatimportance and which has puzzled naval designers for many years. Variousforms of protection has been devised such as blisters and nets, etc.,but most of these devices were extremely cumbersome and were noteffective when the ship was under speed. My present invention solvesthis problem in a new and unique manner without any cumbersome armor orother hindrances to the operation of the ship at full speed. By means ofadetection apparatus comprising a plurality of torpedoshaped feelerswhich are electrically driven from the mother vessel, and which may becontrolled from same and operated far in advance of same, I am able todetect and automatically indicate the position of mines in time toeither reverse the engines and stop the ship or to change the course andget out of the way. This device may also be operated as an advancefeeler by submarines or mine sweepers seeking a channel through enemymine fields. It is believed that this device will be of great value onthe protection of both naval and merchant shipping.

An important object of this invention is to provide a simple and easilyoperated detection device which will give automatic indication when avessel is approaching a mine.

Another object of this invention is to provide a detection system formines which may be operated suificiently far ahead of a moving vessel toeither reverse the engines and stop same or to change the course and getout of the way.

Still another object of my invention is to provide an automatic,electrically operated detection system which will indicate when a vesselis approaching a mine as well as the approximate direction and locationof the mine.

A further object of this invention is to provide a mine detection systemwhich permits operation and automatic indication while the vessel isunder full speed.

Other objects and advantages of my invention will be apparent during thecourse of the following description.

In the accompanying drawings forming a part sulator I4, see Fig. l. I

are connected through insulated leads carried 2 of this specification,and in which like numerals are employed to designate like partsthroughout same,

Figure l is a plan view showing a schematic arrangement of a detectiondevice embodying my invention,

Figure 2* is a sectional elevation of one of the torpedo-shaped feelers,and,

Figure 3 is aschematic diagram of the detection and indicating circuit.

In the drawings, wherein for the purpose of illustration is shown asimplified and preferred arrangement of my invention, the numeral 5designates the ship to be protected. On the forward part of the ship 5are placed reels 6 and I from which cables 8 and 9 extend forward to thetorpedo-shaped detectors or feelers I0 and I I. A cable I2 is connectedwithone end through the insulated lead-in I3 to the feeler Ill and withthe other end to insulator I4. Another cable I5 is connected through theinsulated lead-in I6 to the port feeler II and with its other end toinsulator I4. A mine field comprising mines I'I, I8, I9, 20 and 2| isindicated in dotted. lines, see Fig. 1.

The torpedo-shaped feelers I0 and II are constructed as indicated in thesectional elevation. shown in.Fig. 2. The torpedo-shaped body I0 has apropeller 22 at its forward end. A protective frame 23 prevents damageto the propeller from driftwood or other objects. The propeller 22 isdriven by the electric motor 24 through the gear reduction 25. At itsrear end the torpedoshaped body I0 carries horizontal and verticalrudders 26 and 21 which are operable by means of the electricmotors 28and 29, respectively, through the gear reductions 3B and 3i. The towcable 8 carries several insulated'conductors which provide power andcontrol to the various motors as well as carry thedetection current."The cable "8'is preferably brought to a distribution box 32 from whichseparate connections are brought to the motors and to the insulatedleadins I3 and I6.

-The'detection circuit as illustrated in Fig. 3 consists of the two barecables I2 and I5 which are insulated from one another by means of in-These cables I2 and I5 in the two tow cables 8 and 9 to the variableresistor 33 from which leads 34 and 35 connectto transformer 36 whichagain feeds into the twogrids of tube 31. The sliding member. of thevariable resistor 33 is connected through lead 38 f to one terminal ofcoil 39 0f the power transformer 40 while the other terminal of coil 39is connected to ground through lead 4!. The center tap of transformer 36is connected to the slider of a variable resistor 42 by means of lead43. The remainder of the circuit consists mainly of the amplifying tube44 which has two plates and two grids and which is connected so as toamplify the impulses coming from tube 31, and the two relays 45 and 55.Through leads 4?, 48 and 49 the'relays 45 and 46 may be used to controlautomatic signalling means such as visible indicators or even to controlrudder or engine room signals. The lead 41 is common while 48 indicatesport and 49 starboard. The power transformer 40 furnishes the necessaryoperating voltages and is connected to a suitable source at terminals 50and 5|. The tube 44 is preferably of a type known to the art by thetrade-name Thyratron. It is to be noted, however, that other tubes andother circuits may be used to obtain the same result without departingfrom the object and nature of my invention.

The operation of my invention is as follows: As mentioned supra themotor-driven, torpedoshaped feelers are powered by electric motors andcontrolled from the ship to be protected. These feelers I and I! aresent out ahead of the ship and operated at a suitable distance away fromsame. The electric motors 24 furnish an excess of power thus giving thefeelers a greater speed than the ship 5. In this manner the tow lines 8and 9 will be held taut as will the cables I 2 and [5 due to the factthat the rudders 26 are set so as to give the feelers I0 and I I aslight angle outward from the ship 5. Due to the fact that feelers l0and ll have a higher speed than the ship 5 it is also possible to maketurns at full speed by properly controlling said feelers and by pullingin on one or the other of the cables 8 and 9 if necessary. The feelersare designed to have sufficient buoyancy to float and to carry thecables 8, 9, I2 and I5 and their elevation may furthermore be controlledby means of rudders 21. The electric motors 24, 28 and 29 are preferablyarranged so as to minmize any gyroscopic action.

The bare cables 12 and form one half of a Wheatstone bridge, as shown inFig. 3, with the variable resistor 33 forming the other half. A voltageis applied to this bridge circuit from coil 39 through leads 38 and 4|,the current traveling through the salt water and through the body of thefeelers l0 and H. Normal zeroindication is set by adjusting the variableresistor 33. The cables l2 and 15 are bare and in contact with the saltwater, but are insulated from the bodies of feelerslil and I l by meansof the lead-ins l3 and 16. Being of equal length the resistance ofcables l2 and [5 to ground will also be equal. It is therefore onlynecessary to adjust resistor 33 to obtain perfect balance in the bridgecircuit. 'Ihis'balance is furthermore adjusted to match tube 3'! bymeans of resistor 42. With the bridge on balance no voltage will flow inthe secondary of transformer 36. Any small change in the contact areasof the cables l2 and [5, however, will, immediately result in theupsetting of this balance and a voltage will be induced in transformer35. If, therefore, a mine or any other metallic object comes into thevicinity of one of the cables l2 or I?) the balance will be upset andbeing polarized the induced voltage in transformer 36 will act on eitherone or the other of the grids of tube 37 and accordingly operate eitherone or the other of the plates of the Thyratron 44, thereby operatingeither one of the relays 45 or 46. It is thus not necessary for the mineto touch the cables l2 or 15 and it is obvious that the indication givenwill be proportional in strength to the distance between the mine andthe cable. Thus it is also possible to obtain an indication of thedistance away from the mine as well as whether it is approaching thstarboard or the port cable. In this manner a quick and reliableindication is obtained and it is possible to either stear away or toreverse the engines and stop the ship in time before hittin the mine. Itis to be understood that the form of my invention, herewith shown anddescribed, is to be taken as a preferred example only, and that variouschanges? in the shape, size and arrangement of parts may be resorted to,without departing from the spirit of my invention or the scope of thesubjoined claims.

Having thus described my invention, I claim:

1. A mine detection device for ships comprising a plurality of feelers,said feelers being electrically driven and controlled and operated aheadof the ship to b protected; electrically operated rudder meanscontrolling said feelers; insulated,.multiconductor cables connectingsaid feelers to said ship; a pair of bare cables, mechanically connectedtogether but insulated from each other 'at their connected ends as wellas from the body of said feelers, said bare cablestying said feelerstogether mechanically, and automatic detection means comprising abalanced bridge circuit, of

which said bare cables form one half, whereby-the proximity of mines orother metallic objects may be indicated.

2. A mine detection device for ships, comprising a plurality ofelectrically driven, torpedoshaped feelers operated at a considerabledistance ahead of the ship to be protected; electrically operated ruddermeans whereby said feelers may be controlled from the ship; insulated,multiconductor cables connecting said feelers to said ship; a pair ofbare cables forming a tie between said feelers, said bare cables beinginsulated from one another as Well as from the bodies of .said feelers;a Wheatstone bridge circuit including said bare cables and saidinsulated cables} avariable resistor forming two legs of said bridge.circuit; a polarized amplifying circuit connected to said bridgecircuit, and indicating means operated by said amplifying circuitwhereby the proximity of a mine may be indicated...

3. A mine detection devicefor ships comprising a plurality of feelers,said feelers .being electrically driven and controlled andoperated aheadof the ship to be protected; electrically operated rudder means wherebysaid feelers may be'controlled from the ship; insulated multi-conductorcables connecting said feelers to said ship; alpair of .bare cablesforming'a tie'between 'said feelers, said bare cables being insulatedfrom one another at their common ends as well as fromthe bodies of saidfeelers, said barecabl'es' being connected through insulated lead-ins tosaid insulated multiconductor cables; a potentiometer connected, acrosssaid insulated cables, said bare cables, insulated cables andpotentiometers forming a bridge circuit; a sensitive detectioncirc'iiito'nnected across said potentiometer, and remote control meansoperated by said sensitive detection circuit whereby the proximity ofamine maybe detected.

4. A detector device comprising a plurality of. electrically driventorpedo shaped feelers operated at a considerable distance ahead of theship to be protected; electrically operated rudder means whereby saidfeelers may be controlled from the ship; and insulated multi-conductorcable connecting each of said feelers to said ship; a pair of barecables forming a tie between said feelers; said bare cables being tiedtogether through an insulator at their common end and connected to aseparate lead in said insulated cables through an insulated lead-in insaid feelers; a potentiometer connected across said leads of saidinsulated cables, said potentiometer forming the two arms of a bridgecircuit, while the two other arms are being formed by said bare cables;a sensitive detection circuit connected across said potentiometer andcomprising an input transformer connected into a dual detector and am-15 MICHAEL HENRY LQUGI-INANE.

